try ebay?..its not uncommon to see wrecking yards parting off challengers or the remains of challengers, and you may have some luck scoring a car that would otherwise be totally parted off and awaiting the crusher. If you're willing to do the haul or have it transported, Id imagine this is going to be your best bet there, in casting the widest net possible.
Yeah ive found one that would be perfect but im still waiting on a reply. It took me 2 days to find it so hopefully i can get it for a decent price. Otherwise i think i might have to buy one from an auction, but its hard finding any good ones.